Loud speaker



Nov. 21, 19373.

E. c. JEFFERls LOUD SPEAKER Filed May 10, 1933 l L m N @t -J SLU am; nwww n m N www kvm m. iw: H w- --T-J k m N u. :TM m ww m m\ \\N m an x5.N @NPN Patented Nov. 2l, 1933 srarss PATEnT'Fria 4 Claims.

My invention relates to apparatus for radio reception and particularlythe construction and arrangement of the essential elements of the soundreproducing device, whereby the acoustic effects may be advantageouslyvaried.

As hereinafter described, my invention includes a sound reproducingdevice comprising an outer casing with a horizontal partitionintermediate ci its height supporting a circular diaphragm presented ina horizontal plane beneath a circular opening in said partition,diaphragm being operatively connected with an electric motor forvibrating it with radio impulses; said partition supporting a track inconcentric relation with the axis oi diaphragm, and what I term abell-shaped throat which is a sector of a hollow parabolic shell h /ingat the lower edge thereoi means for engagi'v said track, whereby saidthroat may be Shiite circumierentially with respect to said track. topresent its sound reflecting surfaces in any de ed direction within a'sound ampli hood i "ling the top of said casing and overl-ranging saidthroat and the parts connected therei Said hood is openv at one end forprcwction oi sound waves Vtherefrom under impulses from said diaphragm,and the purpose and effect of making said throat ad` justable asaforesaid in said hood is to vary the volume and tone oi the sounds thusprojected, as hereinafter described.

My invention includes the various novel features oi construction andarrangement hereinafter more definitely specified.

In said drawing, Fig. I is a front elevation of hood and adjustablethroat, the latter being in concentric relation with said hood and inthe position to project the maximum volume of sound from the diaphragm.Fig. II is a vertical sectional view of said structure taken onthe lineII, II, in Fig. I in the direction of the arrows on said line.

In said gures, said casing includes the base 1 supporting the iioor 2and the outer shell 3 including the sound reilecting hood 4 at the topthereof. As indicated, the upper portion of said hood is half of ahollow cone having a rounded back, and

the side walls 5 and 6 oi said casing extend ver-y tically in connectionwith said conical portion so that the entire casing is designed forreflection and projection of sound in the direction to the left of Fig.II.

Said casing Walls 5 and 6 have inwardly eX- tending brackets Tand 8supporting the partition 9 which is normally in stationary position insaid said casing and its appurtenances, including said Said partition 9is provided withA the circular track 14 in concentric relation with se:l open- 65 ing ll and the diaphragm i3 beneath it. The

bell-shaped throat l5 is a sector or" a hoilow parabolic shell havingthe inner sound reflecting surface 16 for projecting the sounds frreproducer laterally with respect to said hood 4.

Said throat l5 has means for engaging said track 14, including thearcuate rib l'l and arcuate ange 18. It is to be understood 'that saidthroat 15 is readily movable circumferentially with respect to saidtrack in concentric relation with the sound reproducing device so that,in the position shown, it projects the maximum volume of sound Wavestoward the left in Fig. II in concentric relation with the outer hood 4of aid casing. However, if said throat l5 ce reversed in positiontopresent its sound reflecting surface 16 at the left in Iig. II, theeiect to project the sound waves toward the bacln'ciosed, portion ofsaid hood 4 and to Very materially minimize the volume of soundprojected. rIhe acoustic effect of the cooperation ci said hood 4 andmovable throat 15 may be advantageously varied by merely turning saidthroat l5 upon its track 14 so that the opera-tor may instantly andreadily control and vary the volume and qua ity of the sound emittedfrom said casing independently of any electrical controlling meansaplpurtenant to said sound reproducing device 12 and, of course, suchmechanical variation of the volume and quality of the sound produced maybe cooperatively employed in conjunction with any electrically operativemeans for controlling the volume and quality of the sound reproduced.

The electrically operative means above contemplated may be ofanyconvenient form. For instance, in Fig. I, I have indicated acontainer 20 for the usual transformers and the container 21 for aseries of evacuated bulbs containing electrodes, one such bulb beingindicated at 22 in Fig. I. Said sound reproducing device l2 is connectedwith the contents of the casing 20 by the electrical conductors 24and'25 and with the casing 21 by the electrical conductors 26 and 27,

and said apparatus is operatively connected with 11 the conductor 28leading to any suitable antenna and with the ground conductor 29.

Said electrically operative means is conveniently supported by the iloor2 within the compartment 30 of said casing shell 3, and I nd itconvenient to normally maintain said compartment closed by the cover 31which is norvmally held in the position shown in Fig. II by its oppositeside flanges 32 and 33 which are indicated in dotted lines. Said cover31 conveniently supports the knobs 35 and 36 by which the electricallyoperative means aforesaid may be manipulated.

Moreover, I find it convenient to provide the opening 37 in the backwall ol' said casing shell 3 with the door 38 which is fitted to slideto and from its closed position shown in Fig. II in the guide anges 39and 40 which are iixed on said casing shell 3. Said opening 37 not onlyaords convenient access to the contents of said compartment 30, but maybe used for Ventilating said compartment which becomes heated during theoperation of the apparatus. Y

However, I do not desire to limit myself to the precise details ofconstruction and arrangement herein set forth, as it is obvious thatVarious modifications may be made therein without departing from theessential features of my invention, as donned in the appended claims.

I claim:

l. In a loud speaker for radio apparatus; the combination with a casingincluding means supporting a diaphragm in a horizontal plane, and

an electrically operative sound reproducing device for vibrating saiddiaphragm; of a horizontally extending track in concentric relation withsaid diaphragm at the top thereof and a bellshaped throat which is asector of a hollow substantially parabolic shell, having means at itssaid diaphragm may be varied by varying the relative position of saidthroat in said hood.

3. In a loud speaker for radio apparatus, the combination with an outercasing having its upper portion forming the half of a hollow cone with arounded back and its side walls extending vertically in continuation ofsaid hood; of a horizontal partition in said casing separating said hoodfrom the lower portion of the casing; said partition having a circularopening therethrough; a sound reproducing device supported by saidpartition and including a diaphragm presented beneath said opening inconcentric relation therewith, and electrically operative means forvibrating said diaphragm; a track supported by said partition, at thetop thereof, in concentric relation with saidk opening; and abell-shaped throat which is a sector of a hollow substantially parabolicshell, having means at its lower edge for engaging said track incircumferentially adjustable relation therewith; whereby sound wavesprojected vertically from said diaphragm may be projected laterally indifferent directions in accordance with the circumferential position ofsaid throat on said track and with acoustic eiects varying in accordancewith the relative position of said throat in said hood.

e, In a loud speaker for radio apparatus, the combination with a soundreproducing device including a circular diaphragm and electricallyoperative means for vibrating said diaphragm; of a bell-shaped throatwhich is a sector of a hollow substantially parabolic shell; and meanssupporting said throat in coaxial relation with said diaphragmY and withfreedom for circumferential adjustment with respect thereto; wherebysound waves projected into said throat parallel with the axis of saiddiaphragm may be projected laterally to said axis, from said throat, indifferent directions in accordance with the circumferential position ofsaid threadincludng a sound reflecting hood overhanging said throat, instationary relation with said sound reproducing device; whereby thevolume and duality of sound projected from said hood in m0 waves formedby said diaphragm may be varied by varying the relative position of saidthroat in said hood.

l lll EDWARD o. JEFFERIS.

